Snap action switch



Nov. 1, 1960 Filed March 18, 1958 M. J. DOBES SNAP ACTION SWITCH 3Sheets-Sheet 1 INVENTOR. MICHAEL J. DOBES Nov. 1, 1960 M. J. DOBES2,958,747

SNAP ACTION SWITCH Filed March 18, 1958 s Sheets-Sheet 2 60 NJ 74H55 K 5I 20/ IIIIIIIIiWH: 42

Figs

VENT MICHAEL J. DOBES Nov. 1, 1960 Filed March 18, 1958 M. J. DOBES SNAPACTION SWITCH 3 Sheets-Sheet 3 INVENTOR. MICHAEL J. DOSES BY mm2,958,747 Patented Nov. 1, 1960 SNAP ACTION swrrcn Michael J. Dobes,Cleveland Heights, Ohio, assignor to The National Acme Company FiledMar. 18, 1958, Ser. No. 722,318

9 Claims. (Cl. 200-78) The invention relates in general to electricalswitches and more particularly to switches wherein electrical contact ismade and broken in a rapid manner.

An object of the invention is to provide a snap action switch whereinthe switch contacts between which electrical connection is made, aremoved relative to each other with rapid acceleration to reduce arcingbetween the contacts and resultant burning and pitting of the same.

Another object of the invention is to provide a switch wherein springmeans is utilized to produce a definite contact pressure between theswitch contacts.

Another object of the invention is to providea switch having anactuating or operating lever which may be arranged to produce eitherright or left hand operation of the switch. 7

Another object of the invention is to provide a snap action switchwherein no wiring is directly connected to the switch proper.

Another object of the invention is to provide a precision quick make,quick break, snap action limit switch which is both oil and water tight.

Another object of the invention is to provide a snap action switchwherein a movable contact is operably connected to a latchable memberwhich latchable member is secured in a given position until a force isbuilt up at which time the latchable member is released thereby quicklymoving the same and the operably connected movable contact.

Other objects and a fuller understanding of this inven tion may be hadby referring to the following description and claims, taken inconjunction with the accompanying drawings, in which:

Figure l is an exploded isometric view, partially in section, of theswitch of the present invention;

'Figure 2 is a side elevational view in section of the switch;

Figure 3 is a view taken generally along the line 3-3 of Figure 2;

Figure 4 is a view taken generally along the line 4-4 of Figure 2;

Figure 5 is a view similar to Figure 4 but showing the switch in aslightly different position;

Figure 6 is a side elevational view showing the switch in the sameposition as it is shown in Figure 5; and

Figure 7 is a view similar to Figures 4 and 5 but show ing the switch instill another position.

The snap action switch of the present invention has been illustrated asa normally closed limit switch of the double make type. The switch isreadily adapted to be converted to a normally open type switch dependingupon the manner in which the external conductors are connected to theswitch as will be described hereinafter. It will also be appreciatedthat the instant switch might be adapted to control two externalcircuits which circuits would be concurrently maintained, one in openand the other in closed condition. s

Referring to Figure l, the snap action switch has been indicatedgenerally by the reference numeral 10 and in eludes in combination amain housing 11 having an open upper end which is adapted to be closedby a cover member 12 and sealed by a gasket 131. Screws 13 maintain thecover member in place upon the housing. Located at one end of thehousing 11 is a cam mechanism 16 which includes first and second parts17 and 18, respectively. The first part of the cam mechanism 16 includesa cam member 20 which is rotatively carried by the cover member 12 by ashaft 21 which is journalled on the cover member. This cam member 20 isprovided with first and second cam portions which might otherwise bereferred to as low and high surface portions 23 and 24, respectively.First and second crossed slots 27 and 28, respectively, are providedupon the end of the cam member 20 opposite the cover 12. The second part18 of the cam mechanism includes a sleeve 31 in which a pivot member 32rotatively resides. The second part 1 8 also includes a raised wallportion 34 which is adapted to reside in either one of the slots 27 or28 to non-rotatively connect the first and second parts 17 and 18 of thecam mechanism 16 together. A cam mechanism return spring 36 surroundsthe sleeve 31 and has two ends which engage either side of a projection'38 .which is formed as an integral part of the housing 11. The secondpart 18 of the cam mechanism is provided with a finger 39 which extendsbetween the two ends of the spring 36. As a result of this constructionwhen the cam mechanism is turned in one direction, and the turning forceis released, one end of the spring 36 will return it to the positionshown in Figures 2 and 3 and when the cam mechanism is turned in theopposite direction, the other end of the spring 36 will return it to theposition shown in Figures 2 and 3. The shaft 21, sleeve 31 and pivot 32together make up what might be referred to generally as pivot means forrotatively mounting the cam mechanism 16. In order to transmit rotativemovement to the cam mechanism, an operating lever 42 is connected to theshaft 21, which is included in the pivot means, and this operating leverresides outside the housing. An engagement roller 44 is journalled atthe end of the operating lever which roller is positioned in the path oftravel of a moving mechanism 46 (Figures 4, 5 and 7) which might be themoving part of nearly any machine, for example, a movable slide. Theoperating lever and the cam mechanism in Figure 4 may be referred to asbeing in a first position whereas in Figure 7 it may be referred to asin a second position. Figure 5 illustrates these parts as beingintermediate the first and second positions.

The end of the housing 11 which is opposite the cam mechanism 16 isprovided with a threaded opening 50 which receives the end of a lengthof electrical conduit 51 (shown only in Figures 2 and 3) within whichtwo conductors 52 and 53, respectively, extend. These conductors extendto an external circuit (not shown) which may control the movement of themoving mechanism 46 illustrated in Figures 4, 5 and 7. A terminal block55 is secured in the bottom of the housing 11 by means of screws 56which extend therethrough and into bosses 57. The terminal block 55 isconstructed of plastic and has a longitudinal slot 60 extendinglengthwise across the upper surface thereof and this slot communicatesat one end portion thereof with the threaded opening 50. First andsecond pairs of terminals 62 and 63, respectively, are located on firstand second end portions, respectively, of the terminal block 55. Onlyone of these terminals is shown in Figure 1 for ease of illustration,however Figure 3 shows both pairs. A terminal of each pair is located oneither side of the longitudinal slot 60. It will be noted that theconductors 52 and 53 extend in the longitudinal slot and areelectrically connected to the terminals of the second pair 63. A firstand second pair of spring biased contacts 65 and 66 are also provided onthe terminal block at the first and second end portions thereof,respectively. The construction of the spring biased contacts is bestseen in Figure 2 of the drawings. A spring biased contact of each of thepairs also resides on either side of the longitudinal slot. Electricalconductors 68 in the form of'a fiat metal strip are positioned on theupper surface of the terminal block for connecting the terminals of eachpair with the respective spring biased contact of each pair.

Positioned immediately above the terminal block is a plastic switchhousing member 72 which is formed into an enclosure for housing fixedand movable electrical contacts which are for the purpose of making andbreaking electrical connection between the conductors 52 and 3 whichlead to the external circuit. First and second pairs of terminal posts74 and 75, respectively, are fixed- 1y embedded in the plastic housingmember 72 at first and second end portions, respectively. With thehousing member 72 in position as shown in Figure 2, these terminal postsengage respectively the first and second pairs of spring biased contacts65 and 66 which are located at either end of the terminal block 55. Itis in this manner that electrical connection is maintained between theexternal circuit and the enclosure of the plastic housing member 72.Each of the first and second pairs of terminal posts is provided with afixed contact 78 which is electrically connected thereto.

A contact carrier 81 is positioned Within the plastic switch housingmember and is movable between first and second positions'therein. Thiscontact carrier carries first and second pairs of movable contacts 83and 84, respectively, and as will be noted, the carrier member isconstructed of a plastic'insulation material. The contacts of each ofthe first and second pairs 83 and 84, respectively, are electricallyconnected together and each pair is biased away from each other by meansof a spring '86. A latchable channel member 90 is slidably supported bythe plastic switch housing member 72 immediately above the contactcarrier 81. The plastic switch housing member 72 has wall means at theupper open end of the enclosure which form a generally rectangularlyshaped dead-ended slot 88 on one side of the V enclosure and a generallyrectangularly shaped openended slot 89 on the other side of theenclosure. The latchable channel includes a back member 92 which hasfirst and second pairs of spaced ieg members or projections 93 and 94,respectively, integrally connected thereto at respective end portionsthereof and these spaced members extend generally laterally of the backmember. First and second carrier pins 96 and 97 are mounted by the backmember and extend into complementary openings 98 and 99 in the contactcarrier for transmitting the movement of the latchable channel to thecontact carrier. The first and second pairs of spaced leg members '93and 94 define a guideway within which a latch release channel 101 islocated for movement between first and second positions and also formovement relative to the spaced leg members as will hereinafter bedescribed. The latch release channel at an intermediate portion thereofhouses first and second relatively movable lugs 103 and 104 and a lugspring or resilient means 105 is positioned between these two lugs andurges them apart. The function of the first lug 103 (Figure 6) is toengage the first pair of spaced members 93 and urge them and as a resulturge the latchable channel to the second position when the latch releasechannel 101 is moved to the second position and the function of thesecond lug 104 is to engage the second pair of spaced members 94 andurge them and as a result urge the latchable channel to the firstposition when the latch release channel moves to the first position. Areturn spring 107 is positioned at one end of the latch release channeland urges the latch release channel to its first position. The other endof the latch release channel is provided with a cam follower roller 108and this roller is located adjacent the cam member 20 and alternatelyengages the first and second surface portions 23 and 24 of the cammember 20. Movement of the cam follower roller 108 from engagement withthe first surface portion 23 of the cam to engagement with the secondsurface portion 24 causes the latch release channel to move from itsfirst to its second position. This progressive movement is best seen in.Figures 4, 5 and 7. An unlatching stud or camming member 109 is fixedlysecured to the latch release channel 101 and is adapted to traveltherewith between the above referred to first and second positions.

A latch plate 111 is located above the enclosure of the plastic switchhousing member 72 and-is secured to the top thereof by means of screws112. The latch plate serves as a cover to confine the latch releasechannel, the latchable channel member and the contact carrier within theenclosure of the plastic switch housing member 72. The latch plate 111is provided with slots 115 which receive the spaced members 93 and 94 ofthe latchable channel. The latch plate also has an opening 116 whichreceives the unlatching stud 109. First and second pairs of latchmembers 118 and 119, respectively, are pivotally connected by means ofpins 120 to first and second end portions of the latch platerespectively. Each of these latch members 118 and 119 has a latchshoulder 122 with which a respective spaced member is engageable andsprings 124 and 125 urge the latch members of a respective pairlaterally toward each other at all times. The latch shoulders 122 of thefirst pair of latch members 118 engage the first pair of spaced members93 when the latch release channel 101 is in the first position (Figures2 and 4). Each of the latch members is provided with a cam surface 126which engages the unlatching stud 109.

The operation of the-snap action switch described hereinabove is asfollows: Assume for the sake of example, that the switch is in the firstposition (Figure 4) with the external circuit by way of the conductors52 and 53 energized and that the mechanism 46 is travelling in a direction indicated by the arrow 1 29. Engagement of the mechanism 46 withthe engagement roller 44 causes the cam mechanism and the cam member 20to rotate in a counterclockwise direction as viewed in Figure 4.Rotation of the cam member 20 causes the cam follower roller 108 on thelatch release channel 101 to travel from engagement with the firstsurface portion 23 to the second surface pos tion 24 of the cam member20. This action initially causes movement of the latch release channel101 from the first toward the second position and also causes the firstlug 103 (Figures 2 and 6) to engage the first pair of spaced members 93which urges the latchable channel 90'to-ward the second "position. Thelatchable channel, however, is initially held from movement toward thesecond position because the latch shoulders 122 on the first pair oflatch members 118 engage the first pair of spaced members 93 and preventmovement of the latchable channel (Figures 4 andS During this period,when the latchable channel is held from movement, the latch releasechannel 101 is moving and the first lug 103 which engages the first pairof spaced members 93 compresses the lug spring 105. This constructiontherefore in the initial movement of the latch release channel permitsrelative movement between this latch release channel and the latchablechannel. The movement of the latch release channel 101 causes movementof the uniatching stud M9 since this stud is fixedly secured thereto.The unlatching stud engages the cam surfaces 126 on the first pair oflatch members; 118 and continues to urge the first pair of latch memberslaterally apart against the urging of spring 124. Upon s'ufiicientlongitudinal movement of the latch release channel, the -unlatching studforces the first pair of latch members far enough apart (Figure 4) sothat the latch shoulders thereon release the first pair of spacedmembers 93 at which time the compressed lug spring 105 by way i of thefirst lug 103 rapidly moves the latchable channel 90 to the secondposition. Since the contact carrier 81 which carries the first andsecond pair of contacts 83 and" 84 is operatively connected to thelatchable channel by means of the pins 96 and 37, it too travels rapidlyfrom. the first to the second position. This rapid movement istransmitted to the first pair of contacts 83 which by way of theirmovement makes electrical connection between the fixed contacts of thefirst pair of terminal posts 74 and the second pairof contacts 84breakselectrical.

connection between the fixed contacts of the second pair of terminalposts 75. t v

When the mechanism 46 moves to-the right from the position shown inFigure 7, the cam mechanism return spring 36 causes the cam member 20 tomove in a clockwise direction from the position inFigure 7 to theposition of Figure 4. While this movement is taking place, the returnspring 107 moves the latch release channel 101 from the second to thefirst position. The movement of the latch release channel from thesecond to the first position causes the snap action switch to functionin much the same way only in reverse of that described hereinabove. Theinitial movement of the latch release channel from the second to thefirst position causes the second lug 104 to engage the second pair ofspaced members 94 to urge the latchable channel to the first positionalong with the latch release channel. The second pair of latch members119, however, engage the second pair of spaced members 94 and preventthe latchable channel member from moving to the first position whichcauses the lug spring 105 to be compressed. Upon further movement of thelatch release channel towards the first position, the unlatching stud109 forces the second pair of latch members 119 far enough laterallyapart to release these latch members from the second pair of spacedmembers 94. This permits the force which has been built up bycompressing the lug spring to act upon the latchable channel member torapidly move the same to the first position. This rapid movement istransmitted to the contacts which are carried by the contact member 81and makes a quick electrical connection between the fixed contacts ofthe second pair of terminal posts 75 and breaks connection between thepair of fixed contacts of the first pair of terminal posts 74. With theexternal conductors 52 and 53 connected, as shown in Figure 2, contacts83 perform no switching function, however, if external conductors wereconnected to terminals 62, then contacts 83 would operate to make thiscircuit while'cont-acts 84 were breaking the circuit of conductors 52and 53 and vice versa. The use of contacts 83 also enables one toconvert the switch to a normally open type by'merely connectingconductors 52 and 53 to terminals 62 rather than 63.

To change the direction of operation of the switch or the switchposition, for example, if the mechanism 46 were located at the lowerright-hand corner of the switch (Figure 4) rather than at the upperright-hand corner, it is only necessary to remove the screws 13 andraise the cover member 12 and rotate the first part 17 of the cammechanism 16 by way of the operating lever 42 in a clockwise directionsubstantially ninety degrees so that the raised wall portion 34 of thesecond part 18 of the cam mechanism interfits with the second slot 28rather than with slot 27. The cover is then re-positioned and fastenedin place by means of the screws 13. The operation of the switch is thesame as described hereinabove, however, it will be seen that thispermits greater latitude in selecting the operational positions of theswitch. The operating lever may also be adjusted relative to the shaft21.

It will thus be seen that a snap action switch has been provided whereinthe quick movement of a movable switch contact relative to a fixedcontact is effected by building up a force tending to move the movablecontact while latching this contact from movement. After a predeterminedforce has been built up, the movable contact is unlatched and the forcewhich is built up can be effectively used at once to bring about a quickaction: This reduces sparking between the contacts and resultant burningand pitting of the same. It necessarily follows that the life of thecontacts is greatly enhanced; The action of the lug spring in moving themovable contacts of the switch also provides a definite contact pressurebetween the switch'contacts giving a positive electrical connection. Theutilization of the plastic housing member 72 with the terminal posts 74and 75 embedded therein and which .make electrical connection with thespring biased contacts of the'terminal block, provides a constructionwherein no wiring is directly connected to the switch proper. Theconstruction of the cam mechanism which includes the first and secondparts 17' and 18 offers a switch construction which can be easilyadjusted to provide either right or left-hand operation of the switch.

Although this invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

1. A snap action switch including in combination a housing, a cover forsaid housing, a cam mechanism comprising first and second parts mountedat one end of said housing, said first part comprising a cam havingfirst and second cam portions, said cam having first and second crossedslots across one end thereof, said second part of said cam mechanismhaving a raised portion thereon interfitting with one of said slots fornonrotatively connectingsaid first and second parts of said cammechanism together, pivot means rotatively mounting said cam mechanism,an operating lever operatively connected to said cam by way of saidpivot means and residing outside said housing, said operating leverhaving an engagement roller on an end portion thereof to transmitmovement from a moving mechanism to move said operating lever from afirst to a second position, a cam spring member engaging said secondpart of said cam mechanism and urging same to a first position, theother end of said housing having a threaded opening to receive a conduitadapted to carry electrical conductors to said housing, a terminal blockhaving first and second end portions and comprising a plastic memberresiding in the bottom of said housing and having a longitudinal slotextending across the upper surface thereof and communicating at one endportion with said'threaded opening, first and second pairs of terminalson said terminal block at said first and second end portionsrespectively, a terminal of each pair residing on either side of saidlongitudinal slot, first and second pairs of spring biased contacts onsaid terminal block at said first and second end portions respectively,a spring biased contact of each pair residing on either side of saidlongitudinal slot, electrical conductors connecting each said terminalwith a respective spring biased contact, a plastic housing member formedinto an enclosure for housing fixed and movable contacts, first andsecond pairs of terminal posts embedded in said plastic housing memberand located at first and second end portions of said housing member andengaging respectively said first and second pair of spring biasedcontacts, first and second pairs of fixed contacts electricallyconnected to said first and second pairs of terminal posts respectively,a plastic contact carrier movable between first and second positions andlocated in said enclosure of said plastic housing member, first andsecond pairs of movable contacts carried by said contact carrier, saidcontacts of each said first and second pair bein electrically connectedtogether, spring means urging said first and second pairs of movablecontacts away from each other, a latchable channel supported by saidplastic,

housing member above said plastic contact carrier and including abackmember having first and second pairs of spaced members at respective endportions thereof extending *generally laterallytherefrom, said spacedmembers defining a'guideway, first and second carrier pins mounted onsaid'back member and extending into complementary openings in saidcontact carrier for moving said contact carrier between said first andsecond positions, a latch release channel residing in said guidewaybetween said spaced members for movement between first and secondpositions and relative to said spaced members, first and secondrelatively movable lugscarried by said latchrelease channel, a logspring between said first and second lugs urging them apart, said firstlug engaging said first pair of spaced members and urging said latchablechannel to 'said's'econd position on movement of said latch releasechannel toward said second position, said second lug engaging saidsecond pair of spaced members and urgingsaid latchable channel to saidfirst position on movement of said latch release channel toward saidfirst position, return spring means urging said latch release channel tosaid first position, an unlatching stud carried by said latch releasechannel, a cam follower roller carried by one'end of said latch releasechannel and residing adjacent said cam, a latch plate secured to saidplastic housing member and covering said-enclosure, said latch platehaving slots for the reception of said spaced members of said latchablechannel and having an opening for the reception of said unlatching stud,first and second pairs of latch members pivotally connected to first andsecond-end portions of said latch plate respectively, each said latchmember'having a latoh'shoulder with which a respective spaced member isengageable, and having cam surfaces engageable by said unlatching studto move the same to unlatched condition, spring means urging said latchmembers of each pair laterally toward each other to latched condition,said latch shoulders of said first pair of latch members engaging saidfirst pair of spaced members in the first position of said latch releasechannel to prevent movement of said latchable channel to said secondposition until said unlatching stud unlatches said first pair of latchmembers.

2. A snap action switch including in combination a housing having anopening closed by a cover, a cam mechanism comprising first and secondparts mounted at one end of said housing, pivot means rotativelymounting said first and second parts of said cam mechanism, meansconnecting said first and second parts and permitting angular adjustmentof said first and second parts relative to each other, an operatinglever operatively connected to partially rotate said cam mechanism byway of said pivot means "and residing outside said housing, saidoperating lever having an engagement roller on an end portion thereof totransmit movement from a mechanism to move said operating lever from afirst to a second position, a spring member urging said cam mechanism toa first position, a terminal block in said housing, terminals on saidterminal block for connection with external conductors, spring biasedcontacts on said terminal block, electrical conductors connecting saidterminals with a respective spring biased contact, an electricallyinsulated housing member formed into an enclosure for housing fixed andmovable contacts, terminal posts embedded in said electrically insulatedhousing member and engaging at one end portion thereof a re spectivespring biased contact, a fixed contact electrically connected to eachsaid terminal post at another end portion thereof, an electricallyinsulated contact carrier movable between first and second positions andlocated in said enclosure of said housing member, movable contactscarried by said contact carrier and engageable with said fixed contacts,a latchable channel supported by said housing member above said contactcarrier and including a back member having first and second spacedmembers extending generally laterally therefrom, means connect urgingsaid latchable channel and hence said contact carrier 'to said secondposition on movement of said latch release channel toward said secondposition, said second lug engaging the other of said spaced members andurging said latchable'channel and hence said contact carrier-to saidfirst position on movement of said latch release channel toward saidfirst position, return spring means urging said latch release channel tosaid first position, an unlatching stud carried by said latch releasechannel, a cam follower carried byone end of said latch release channeland residing adjacent-and engageable with said 'cam mechanism, a latchplate having slots for the reception of said spaced members of saidlatchable channel and having-an opening for the reception of saidunlatching stud, latch members pivotally connected to said latch plate,each said latch member having a latch shoulder with which a spacedmember is engageable and having an actuating surface engageable by saidunlatching stud to move the latch member to unlatched condition, springmeans urging said latch members to a latched condition, said latchshoulders of said latch members engaging one of said spaced members inthe first position of said latch release channel to prevent movement ofsaid latchable channel to said second position until said unlatchingstud unlatches said latch members.

3, A snap action switch including in combination a housing, a cammechanism mounted in saidhousing, pivot means rotatively mounting saidcam mechanism, an operating lever operatively connected to said cam byway of said pivot means and residing outside said housing, saidoperating lever having an end portion adapted to be engaged by a movingmechanism to move said operating lever from a first to a secondposition, an electrically insulated switch housing formed into anenclosure for housing contacts, terminal posts in said electricallyinsulated housing and at one end portion thereof being electricallyconnected to external conductors, a fixed contact electrically connectedto each said terminal post at another end portion thereof, a contactcarrier movable between first and second positions and located in saidenclosure of said switch housing, movable contacts carried by saidcontact carrier and engageable with said fixed contacts, a latchablechannel supported by said switch housing above said contact carrier andincluding a back member having first and second spaced members extendingtherefrom, means connecting said contact carrier and said latchablechannel together, a latch release channel residing adjacent said spacedmembers for movement between first and second positions and relative tosaid spaced members, first and second lugs carried by said latch releasechannel, a spring between said first and second lugs urging them apart,said first lug engaging said first spaced member and urging'saidlatchable channel to said second position on movement of said latchrelease channel toward said second position, said second lug engagingsaid second spaced member and urging said latchable channel to saidfirst position on movement of said latch release channel toward saidfirst posit-ion, spring means urging said latch release channel to saidfirst position, an unlatching stud carried by said latch releasechannel, a cam follower carried by one end of said latch release channeland residing adjacent said cam mechanism and adapted to be engagedthereby, a latch plate having slots for the reception of said spacedmembers of said latchable channel and having an opening for thereception of said unlatching stud, latch members connected to said latchplate, each said latch member having a latch shoulder with i which aspaced member is engageable and having actuating surfaces engageable bysaid unlatching stud to move the same to unlatched condition, meansurging said latch members to latched conditions, said latch shouldersofa portion of said latch members engaging one of said spaced members inthe first position of said latch release channel to prevent movement ofsaid latchable channel to said second position until said unlatchingstud unlatches said engaged portion of said latchmembers. l

4. A snap action switch including in combination a housing having anopen upper end closed by a cover member, a terminal block secured insaid housing and having spring biased contacts, means for providingelectrical connection between said spring biased contacts and externalelectrical conductors, a plastic switch housing having wall meansforming an enclosure, terminal posts embedded in said plastic switchhousing with one end portion thereof engaging said spring biasedcontacts and the other end portion extending into said enclosure, fixedcontacts secured to said terminal posts, a plastic contact carrierlocated in said enclosure for movement between first and secondpositions, movable contacts carried by said contact carrier andengageable with said fixed contacts, a latchable member mounted by saidplastic switch housing for sliding movement between said first andsecond positions, projections secured to and extending from saidlatchable member, means operably connecting said plastic contact carrierand said latchable member together, an unlatching member slidablymounted on said latchable member between first and second positions, lugmeans carried by said unlatching member and engaging said projections,spring means carried by said unlatching member and engaging said lugmeans for permitting relative movement between said latchable andunlatching members, a latch plate secured to said plastic switch housingopposite said terminal block and covering said enclosure, latch memberspivotally carried by saidlatch plate and engageable with saidprojections for latching said latchable member in a fixed position, astud carried by said unlatching member and engageable with said latchmembers for unlatching said latchable member to permit movement of saidlatchable member from said fixed position, a cam follower roller mountedon one end of said unlatching member, a plural part cam mechanismrotatively mounted in said housing adjacent said cam follower roller formoving said unlatching member to said second position, one of said camparts having first and second cam surfaces for alternate engagement withsaid cam follower roller and having wall means defining a plurality ofslots, another of said cam parts having a raised wall interfittable in aselected one of said plurality of slots for rotatively connecting saidcam parts, a cam spring biasing said another of said cam parts to apredetermined position, an operating lever connected to said one of saidcam parts and extending externally of said housing and located in thepath of movement of a moving mechanism, and a return spring for movingsaid unlatching member to said first position.

5. A snap action switch including in combination a main housing havingan open end closed by a cover member, a terminal block secured in saidhousing and having spring biased contacts, means for providingelectrical connection between said spring biased contacts and externalelectrical conductors, a plastic switch housing having wall meansforming an enclosure, terminal posts embedded in said plastic switchhousing with one end portion thereof engaging said spring biasedcontacts and the other end portion extending into said enclosure, aplastic contact carrier located in said enclosure for movement betweenfirst and second positions, contact means carried by said contactcarrier and engageable with said terminal posts, a latchable membermounted by said plastic switch housing for movement between first andsecond positions, projection means extending from said latchable member,means operably connecting said plastic contact carrier and spasm;

said latchable member together, an unlatching member slidably mountedadjacent said latchable memberjlug means carried by said unlatchingmember and engageable with said projection means, spring means carriedby said unlatching member and engaging said lug means for permittingrelative movement between said latchable and unlatching members, a latchplate secured to said plastic switch housing opposite said terminalblock and covering said enclosure, a latch member carried by said latchplate and engageable with said projection means for latching saidlatchable member, a stud carried by said unlatching member andengageable with said latch member for unlatching said latchable member,a cam follower mounted by one end of said unlatching member, a cammechanism including first and second parts rotatively mounted in saidhousing adjacent said cam follower for engaging and moving said camfollower, said first cam mechanism part having wall means defining aplurality of slots, said second cam mechanism having a raised wallinterfittable in a selected one of said plurality of slots forrotatively connecting said first and second cam mechanism parts at apredetermined angular position relative to each other, a cam springbiasing said cam mechanism to a predetermined position, an operatinglever connected to said cam mechanism and extending externally of saidmain housing, and a return spring for moving said unlatching member tosaid first position.

6. A snap switch including in combination -a main housing, a switchhousing in said main housing and having wall means forming an enclosure,terminal posts in'said switch housing with one end portion thereofadapted to be electrically connected to external conductors and theother end portion extending into said enclosure, said end portions ofsaid terminal posts in said enclosure having fixed contacts, a contactcarrier located in said enclosure for movement between first and secondpositions, contacts carried by said contact carrier and engageable withsaid fixed contacts, a latchable member adapted for movement betweenfirst and second positions, means operably connecting said contactcarrier and said latchable member together, an unlatching member mountedfor movement between first and second positions, a latch plate securedto said switch housing and covering said enclosure, first and secondlatch means carried by said latch plate and engageable with saidlatchable member for latching the same, a camming member carried by saidunlatching member and engageable with said first latch means in movingfrom said first to said second position for unlatching said latchablemember and engageable with said second latch means in moving from saidsecond to said first position for unlatching said latchable member,means for moving said unlatching member from said first to said secondposition, means for moving said unlatching member from said second tosaid first position, first lug means carried by said unlatching memberand engaging said latchable member, second lug means carried by saidunlatching member and engaging said latchable member, spring meansacting between said unlatching memberand said first lug means forpermitting relative movement between said latchable and unlatchingmembers whereupon said spring means is loaded upon movement of saidunlatching member from said first to said second position until saidcamming member carried by said unlatching member engages and unlatchessaid first latch means whereupon said loaded spring means is releasedand said latchable member rapidly moves to said second position, springmeans also acting between said unlatching member and said second lugmeans for permitting relative movement between said latchable andunlatching members whereupon said spring means is loaded upon movementofsaid unlatching member from said second to said first position untilsaid cam member carried by said unlatching member engages and unlatchessaid second latch means whereupon said loaded spring means is releasedand said latchable member rapidly moves to said first position. I

7. A snap action switch including in combination a main housing havingan open end closed by a cover member, a terminal block secured in saidhousing and having contacts, means for providing electrical connectionbetween said contacts and external electrical conductors, a plasticswitch housing, wall means forming an open ended enclosure which extendsfrom one side of said switch housing thereinto, terminals embedded insaid plastic switch housing with one end portionthereof engaging saidcontacts and the other end portion extending into said enclosure, wallmeans at said one side of said plastic switch housing defining agenerally rectangularly shaped dead-ended slot on one side of saidenclosure and defining a generally rectangularly shaped open ended sloton the other side of said enclosure, a plastic contact carrier locatedin the bottom of said enclosure for movement between first and secondpositions, first and second contact means spring'biased away from eachother and carried by said contact carrier and engageable with said otherend portion of said terminals which extend into said enclosure, alatchable member having first and second end portions, said first endportion of said latchable member residing in said deadended slot "andsaid second end portion thereof residing in said open ended slot withthe intermediate portion thereof overlying said enclosure, first andsecond projection means secured to either side of said latchable memberand extending upwardly therefrom, pin means on the bottom side of saidlatchable member and extending into said plastic contact carrier tooperably con nect the two together, an unlatching member slidablymounted on said latchable member between said first and secondprojection means, first and second lugs carried by said unlatchingmember and being spaced from each other, said lugs extending laterallyof said unlatching member and adapted to engage said projection means onsaid latchable member upon movement of said unlatching member, springmeans between said first and second lugs normally biasing them apart, alatch plate secured to said open end of said enclosure to close thesame, wall means defining openings in said latch plate through which atleast a portion of said first and second projection means extend, firstand second latch means pivotally mounted flatwise on said latch platefor latching and unlatching said latchable member by engaging anddisengaging said at least a portion of said first and second projectionmeans, a stud carried by said unlatching member, wall means defininganother opening in said latch plate through which said stud extends,said stud being engageable with said first and second latch means forunlatching said latchable member, said unlatching member being movablebetween first and second positions, cam means for moving said unlatchingmember from said first to said second position, a spring memberpositioned in said dead-ended slot and engaging said unlatching memberfor moving said unlatching member from said second to said firstposition.

8. A snap action switch including in combination a main housing havingan open end closed by a cover member, a switch housing in said mainhousing, wall means forming an open ended enclosure which extends fromone side of said switch housing thereinto, terminal means extendingthrough said switch housing with one end portion thereof beingelectrically connected to external conductors and the other end portionextending into said enclosure, wall means at an upper portion of saidswitch housing defining a dead-ended slot on one side of said enclosureat said open end thereof and defining on open ended slot on the otherside of said enclosure at said open end thereof, a contact carrierlocated in said enclosure for movement between first and secondpositions, first and second contact means spring biased away from eachother and carried by said contact carrier and engageable with said otherend portion of said terminals which extend into said enclosure, a latchable member having first and second end portions, said first end portionof said latchable member residing .in said dead-ended'slotandsaid secondend portion thereofres-iding in sai'dlopen ended slot with theintermediate 'portionthere'of'overlying said open ended enclosure, firstand second projection means secured to either side of said latchablemember and extending therefrom, means "operably connecting saidlatchable member and said contact carrier together, an unlatching memberslidably mounted on said latchable member between said first and secondprojection means,-first and second lugs carried .by said unlatchingmember and being spaced from each other, said lugs extending laterallyof said unlatching member and adapted to engage said projection means onsaid latchable member upon movement of said unlatching member, springmeans between said first and second lugs normally biasing them apart, alatch plate secured to said open end of said enclosure to close thesame, wall means defining openings in said latch plate through which atleast a portion of said first and second projection means extend, firstand second latch means pivotally mounted flatwise on said latch platefor latching and unlatching said latchable member by engaging anddisengaging said at least a portion of said first and second projectionmeans, a camming member carried by said unlatching member, wall meansdefining another opening in said latch plate through which said cammingmember extends, said camming member being engageable with said first andsecond latch means for unlatching said latchable member, said unlatchingmember being movable between first and second positions, means formoving said unlatching member from said first to said second position, aspring member positioned in said dead-ended slot and engaging saidunlatching member for moving said unlatching member from said second tosaid first position.

9. A snap action switch including in combination a main housing havingan open end closed by a cover member, a switch housing having contactmeans therein adapted to be electrically connected to externalconductors, wall means forming an open ended enclosure which extendsfrom one side of said switch housing thereinto, wall means at an upperportion of said plastic switch housing defining a dead-ended slot on oneside of said enclosure and defining an open ended slot on the other sideof said enclosure, 2. contact carrier located in said enclosure formovement between first and second positions, contact means carried bysaid contact carrier and engageable with said contact means in saidenclosure, a latchable member having first and second end portions, saidfirst end portion of said latchable member residing in said dead-endedslot and said second end portion thereof residing in said open endedslot with the intermediate portion thereof overlying said open endedenclosure, first and second projection means secured to either side ofsaid latchable member and extending therefrom, means operably connectingsaid latchable member and said contact carrier together, an unlatchingmember slidably mounted on said latchable member between said first andsecond projection means, lug means carried by said unlatching member andadapted to engage said projection means on said latchable member uponmovement of said unlatching member, a latch plate secured to said openend of said enclosure to close the same, wall means defining openings insaid latch plate through which at least a portion of said first andsecond projection means extend, first and second latch means pivotallymounted flatwise on said latch plate 'for latching and unlatching saidlatchable member by engaging and disengaging said at least a portion ofsaid first and second projection means, a camming member carried by saidunlatching member, wall means defining another opening in said latchplate through which said camming member extends, said camming memberbeing engageable with said first and second latch means for unlatchingsaid 13 latchable member, said unlatching member being movable betweenfirst and second positions, and means for moving said unlatching memberbetween said first and second positions.

References Cited in the file of this patent UNITED STATES PATENTS1,559,329 Lemlyn Oct. 27, 1925 14 Chrastina Nov. 21, 1950 Jefirey Feb.26, 1957 Mayzik Mar. 25, 1958 FOREIGN PATENTS France June 13, 1936

